None of the politicians are talking about it, but threats to freedom of speech have emerged in three different guises in the first three weeks of the election campaign.

First there was the assailing of Duncan Storrar by that bastion of free speech, News Corp, for having had the nerve to put his head above the parapet on the ABC TV program Q&A, by questioning the fairness of the federal budget.

The newspaper company dredged up his criminal history – his last conviction was eight years ago – and revealed unhappy aspects of his family life.

It was a chilling spectacle for other private citizens. Despite a disability and poor education, Storrar wished to make himself heard in the national debate.

The second case concerned Dr Peter Young, psychiatrist and whistleblower.

Young was responsible for supervising mental health services to asylum seekers in all Australian-run detention centres from 2011 to mid-2014. In this capacity he was employed by International Health Management Services (IHMS), a company contracted to the federal government.

In 2014, giving evidence to an Australian Human Rights Commission inquiry into children in detention, Young said that the Immigration Department had been told several weeks earlier about the prevalence of mental health problems among child detainees. He told the inquiry that the department had ordered the figures be removed from a report.

Now it emerges that he has been a target of an Australian Federal Police investigation.

The Guardian Australia reported on May 24 that the Australian Federal Police (AFP) had compiled hundreds of pages of file notes and reports on Young, including documents that showed his phone records had been investigated.

The newspaper reported that the Department of Immigration had sought an investigation by the AFP after the publication in media reports of the medical records of Hamid Khazaei, an asylum seeker detained on Manus Island. Khazaei died from septicaemia in September 2014, provoking strong criticism of the government’s asylum-seeker policies.

Young had subsequently requested access to files the AFP had compiled on him. According to the newspaper, the files stated that Young was a suspect in the investigation of the leaking of Khazaei’s records, because of “comments attributed to him being highly critical of [the Immigration Department] and IHMS in their handling of asylum seeker medical care” in two news reports.

However, the police examination of Young’s phone metadata revealed that he had had no contact with the media when the articles on Khazaei were published.

Young was quoted by The Guardian as saying that, in addition to accessing his metadata, the AFP had contacted his colleagues and questioned them about why they were speaking to him.

The third case also involves the AFP.

Last week, they made a fine election-time media spectacle of a raid on the home of a staffer for Labor’s communications spokesman, Jason Clare.

Television cameras and a scrimmage of media accompanied the officers to a home in Brunswick in Melbourne’s inner north. When the door opened a woman occupant was caught in a fusillade of flashbulbs.

On the same day, the AFP also raided the parliamentary office of the former Labor communications minister, Stephen Conroy, in the more restricted confines of the Commonwealth Offices in Treasury Place, East Melbourne.

This time the police were investigating the leaking of documents concerning cost blow-outs and other embarrassments surrounding the roll-out of the National Broadband Network (NBN).

Having the media along for the ride seemed designed to show how unpleasant the AFP can make life for people who dare to embarrass the government.

These episodes raise several questions:

When big media start banging on about freedom of speech, whose speech are they clamouring to protect? Just their own or everyone else’s too?

How effective are Australia’s whistleblower laws in protecting people who speak out on matters of public interest, as Young did?

Is government embarrassment a sufficient reason to punish disclosure?

Does the AFP display an appropriate degree of operational independence?

The force has a long history of going after whistleblowers, even when the subject matter has nothing to do with terrorism, national security or serious crime.

One of the more egregious examples occurred in 2004 when the AFP prosecuted a Commonwealth public servant – unsuccessfully, as it turned out – for allegedly disclosing material proving the Howard government was lying about the effects of changes to war veterans’ welfare entitlements.

The public servant was acquitted on appeal, but the proceedings ensnared the two Herald Sun reporters who wrote the story. This ultimately resulted in them being convicted of contempt of court for refusing to disclose the identity of their confidential source.

The law that enables the AFP to embark on these oppressive operations is a catch-all secrecy provision, Section 70 of the Commonwealth Crimes Act. Like its contemporary successors, including the Anti-Terrorism Act (No 2) 2005, and the National Security Legislation Amendment Act (No 1) 2014, Section 70 contains no public-interest defence with which whistleblowers and journalists might defend themselves in the event of prosecution.

All this suits both sides of politics, so we are not likely to hear anything about it from the campaigning politicians. But three obvious remedies suggest themselves: putting a public-interest defence in the various laws, making the whistleblower laws more effective, and changing the craven culture of the AFP.